There is a spreadsheet circulating around somewhere (from a TEST member) that gives an estimate for each ship's UEC price. The sheet is based on a 3:33 to 1 in rec vs released ship prices plus the size of the ship which was mentioned by CIG as playing a role in cost.
The top of the list (if I remember correctly) is a 1:31 for the titan which prices about 1.5M. Other ships that are high on the list is hammerhead, 300, 315, 325 and freelancer.
What you could do is buy upgrades for all your small ships to these ships listed above. The upgrades are cheap and in some cases cost zero dollars. If Ships can be sold ingame (without supply/demand factor) then you are covered. If not then you didn't spend that much on upgrades and so you could just melt it.
Edit: Here is an example.
You have a Cyclone which costs like 30k UEC. Buy the upgrade for it to a Titan which costs you nothing or maybe $5. If the release game lets you sell ships freely then you can upgrade the Cyclone to a Titan. Sell the Titan and use that UEC to buy the Cyclone back ingame. If the game doesn't let you sell ships then you have $5 credit.